Well I changed the fuel filter on the 96 and thought while I was at it I would do the oil and filter too. Now I have an engine knock. Could it be something i have done? I did notice I put a little too much oil in the crankcase ( it's up on the o in operating range) could that have something to do with it? Fuel filter made a huge difference and on the test drive the thing would pull a whole lot better then I must have picked up a little air in the fuel cause it hesitaed just a bit and the service engine light came on. I figured it had some thing to do with the fuel so I removed the negative battery cable to clear the code. Thought I'd take it for another little spin and on the way home all was well running great and I noticed the knock. When I pulled in the driveway it was really noticeable. It seems to come and go. Got me stumped.

The code would probably help to pinpoint what may be wrong.
The fuel filter change opens the possability that trash got past the filter housing and into the IP.

Could be the crank pulley

Okay let's say something did get past the filter to the IP what's that mean? This is my first deisel and surely with only a tad over 100k it's not giving up the ghost yet. The service engine light isn't on anymore so I assume that means no codes? I'm gonna drain some of the oil today I know there is a bit too much in the crankcase.


What else could it be? Like I said everything was great even after the fuel filter change until I changed the oil. I used Rotella T 15w40. This is it's girst change since I've owned it.


If it needs it what am I looking at for an overhaul.


96 K3500 4x4 5 spd

Trash getting past the filter would cause a hesitation in the engine.

Too much oil puts more pressure on the piston rings.

rebuilds cost thousands unless you do it yourself.

I figured the hesitation was from trash or air, but now there is no hesitation. No codes, runs better than ever, There couldn't be more than a quart of extra oil in there. It's gotta be something silly, this is crazy. The knock comes and goes.


I geuss it could be that the dealer had it full of something thick when I bought it to hide the knock.http://www.dieselplace.com/forum/smileys/Cry.gif

Sometimes loose bolts on mounting brackets will knock. As well as the exhaust/turbo assembly.
Even the aluminum heater hose can knock if loose.

If it was a sticky valve(s) the engine would hesitate more and jump at idle.

I had a knock on my '94 that went away when I installed a mandrel bent downpipe and straight exhaust.
it could be something simple as a loose clamp on the downpipe/turbo outlet.

I've looked all over the thing for something loose and can't find anything. Like I said it runs like a dream, it just knocks. More power than ever. The only thing that makes any sense to me is the dealer I bought it from had a real thick oil in it to hide the knock and when I went back to 15w40 it came back. The knock is definately coming from the engine not the turbo or anywhere else. It's internal whatever it is. Geuss I'll take it to a mechanic if my dad can't figure it out this weekend. Local GM dealer won't do anything but service deisel.

Drained just a lil over a quart of oil out to get it back into operating range. Seemed the knock got softer. So I thought what the hey let's drive it to town and by the time I got back the knock was gone and it was running like normal. Could it have been the oil? Or do I have a valve sticking?http://www.dieselplace.com/forum/smileys/Clap.gif

A quart is a lot to overfill it. You can blow your compression like that.